[bbq2]: Should `ArcBBQueue` implement `BbqHandle`?

[all-is-to-be-dared]

As the title says.

This might just be a docs issue, but I had expected to be able to do something like:

let x : FramedProducer<GogiGui> = bbq.framed_producer();

My main issue here is that it's instead required to write FramedProducer<Arc<BBQueue<BoxedSlice, AtomicCoord, Blocking>>>.

Three courses I can see:

1. Leave it be
2. Make typedefs for prod/cons for all the nicknames
3. Have ArcBBQueue implement BbqHandle

Not really sure which one you prefer here.